Thermal Engine Encapsulation (TEE) is a technique for reducing
heat loss from an engine after it has been switched off, in order
to get a warmer re-start. This practice yields benefits in terms of
fuel economy, emissions and wear, especially for vehicles used for
short journeys in cold weather and with engines warming up
slowly.
In this study, the encapsulation of a small automotive diesel
engine is investigated by means of theoretical and experimental
analyses. In particular, the influence of oil temperature on brake
specific fuel consumption and emissions is calculated. Furthermore,
the thermal behavior of the engine has been simulated by a
lumped-capacitance model, in order to assess the correlation
between encapsulation thickness and cool-down time.
Finally, the 0-D thermal model and the 1-D engine model have
been coupled in order to predict the influence of engine cranking
temperature on fuel consumption and pollutant emissions,
considering a B-class vehicle running a short journey (15 minutes)
at medium speed and load and very low external temperature
(0°C).